Since then, I’ve been painstakingly pushing my music collection consisting of about 18,000 tracks into the cloud (I’m 2,643 tracks in as I write this; Google’s storage limit is 20,000 songs).

Being able to do this is a relief because I worry about data stored on physical media but not backed up online. Copies of all my e-mails are in the cloud (via Gmail), as are all my most precious photos (via Flickr) and videos (via Flickr and YouTube). I back up data via Dropbox and CrashPlan, too.

Music Beta fills a need for me because it not only archives my music but allows me to interact with it via computers as well as mobile devices. In essence, I have a music player in the sky I can use anytime, without having to sync music files from one device to another.

This is huge, especially with extra touches such as offline-playing capability and the ability to assemble instant playlists.

I’ve been testing Music Beta’s Web interface on my Mac, and on an Android handset via an updated Music app, but not long enough to know whether it’s a service I’ll continue to use. But merely having all my music on it is a load off my mind.

Offline apps. I swear by Google Docs, but it has its frustrations. Its lousy performance on mobile devices is an annoyance (which I detail here). My inability to work offline is headache — my productivity tanks without an Internet connection.

So I’m happy that Google will soon offer fully offline-ready versions of Google Docs, plus Gmail and Google Calendar. Now, if Google can also make Google Docs fully mobile-friendly, I’ll be a happy camper.

Chromebooks. In the so-called “post-PC” era, there are warring notions of what simplified, streamlined devices people will use for productivity and communication. Tablets — especially Apple’s iPads — are popular, of course, and Google is active in this space with its Android operating system.

But Google is also pushing the “Chromebook,” which is a stripped-down laptop using a version of the Chrome browser as its operating system. That’s all you see when you open the lid: Chrome. This video explains it nicely:

I’m enthusiastic about this concept, especially since all my stuff is in the cloud already, but I’m painfully aware of limitations after using a prototype Chromebook with its so-called Chrome OS.

It is a big hassle to deal with files. YouTube videos play fine, but I can’t use Netflix or Hulu. I’m dependent on an Internet connection to get most of my stuff done.

That’s why I’m excited about Chrome OS improvements that include a file manager, beefed-up media capabilities that include Netflix and Hulu playback, and the aforementioned offline modes in Google Docs, Gmail and Google Calendar. Music Beta will work on a Chromebook, of course, and even Angry Birds is now available via the Chrome Web Store.

None of this would mean anything without Chromebooks that are shipping to consumers. So good news: Samsung and Acer will begin selling Chrome OS notebooks in a few weeks. I’m tempted to make a purchase, and I can pretty much guarantee some kind of Chromebook figures into my long-term computing future.

Movie rentals. One big part of my Apple experience is online movie rentals via the iTunes Store, which is available on Macs and PCs (via the iTunes desktop app) and on iOS devices and the Apple TV box. Movie night at my house is as likely to involve an online rental as a Netflix or Redbox DVD rental.

Google needs to compete, and it’s doing so.

It’s offering movie rentals on computers via YouTube and the Android Market (this is essentially one rental service with two online places to access it) and, soon, on Android devices.

The Motorola Xoom tablet is the first to get this feature via a software update (the over-the-air Android upgrade is rolling out now). I have a Xoom; I’m waiting for the update to hit it so I can watch a Harry Potter movie I rented.